Safety of Reusing Bottled Water Containers

Reusing plastic bottles reduces waste and energy used for disposal or recycling.

Questions about the safety of reusing plastic water bottles arose after a 2002 "Canadian Journal of Public Health" study found fecal bacterial contamination in almost 9 percent of elementary students' water bottles (see References 1, page 1). On the heels of that study, mass-forwarded emails began claiming that freezing or heating plastic water bottles could cause cancer-causing chemicals to leach out of the plastic and into the water (see References 2). If you are an eco-friendly consumer who reuses rather than disposes of those plastic bottles, you may justifiably wonder if the risks outweigh the benefits.

Freezing Plastics

Refilling a plastic water bottle and popping it into the freezer overnight to enjoy an ice-cold, eco-friendly drink the next morning seemed to become more perilous when popular forwarded emails claimed that dioxins -- a group of known carcinogenic chemicals -- would leach from bottles put in the freezer. Although the emails cited the information as coming from the Johns Hopkins Bloomberg School of Public Health, Johns Hopkins professor Rolf Halden set the record straight and declared the email claim a hoax in a June 2004 article on the school's website. Plastic water bottles don't contain dioxins, and freezing plastics makes it less likely, rather than more likely, that harmful chemicals will leach into the water. (See References 3)

Bacterial Contamination

The "Canadian Journal of Public Health" study also has a potentially chilling effect on the practice of reusing plastic water bottles. In this study, bacterial levels exceeded safe water standards in more than 64 percent of elementary students' reusable water bottles tested (see References 1, page 1). The researchers, however, did not attribute their findings to the reuse of plastic water bottles; they instead found that poor hand-washing habits among the students introduced potentially dangerous bacteria into the classroom, a common problem among populations of young students (see References 1, page 2). Furthermore, the researchers point out that the school did not instruct the students to wash the water bottles, and some students reused the same bottle for months without washing it (see References 1, page 1).

Dangerous Plastics

When heated, some plastics leach chemicals into any food or beverage with which they come into contact. For this reason, if the label warns against use for hot foods or beverages, you should use the plastic product for cold foods or beverages only (see References 3). Plastic water bottles are generally made of polyethylene terephthalate plastics, which the U.S. Food and Drug Administration has approved for use both as a food container and for cooking foods (see References 4).

Eco-Friendly Practices

The U.S. Environmental Protection Agency recommends reusing water bottles to reduce the amount of waste that U.S. households generate (see References 5). Wash and completely dry your water bottle between uses. Investing in a wide-mouth reusable bottle makes cleaning easier. Check any plastic containers for warnings before you leave them in a hot car or use them in a microwave (see References 3).